如果您对餐饮服务不满意，可以用以下英文句子进行投诉：

1.I'm sorry to say that I'm not satisfied with the food/service.

2.I had a bad experience with the restaurant.

3.There was something wrong with the order I received.

4.The food was cold/tasteless/inedible.

5.The service was slow/unfriendly/incompetent.

6.I was charged for something that I didn't order.

7.I feel like I didn't get value for my money.

8.Can you please refund my money/send someone to talk to me?

9.I'd appreciate it if you could resolve this matter as soon as possible.

10.I'm looking forward to hearing back from you soon.

请注意，在投诉时应该保持礼貌和尊重，并提供详细的信息和证据，以便餐厅能够更好地解决问题。